<!doctype html> 
<html> 
<head> 
    <meta charset="utf-8"> 
    <title></title> 
</head>
<body>
<script type="text/javascript">

var a = [1,2,3];
//a.length

alert(typeof a.join(''));
alert(a.join(''));

	
	
</script>
</body>
</html>